Buggy code:
private static final Properties defaultStrategies ; private boolean detectAllHandlerMappings = true ; private boolean detectAllHandlerAdapters = true ; private boolean detectAllHandlerExceptionResolvers = true ; private boolean detectAllViewResolvers = true ; private boolean throwExceptionIfNoHandlerFound = false ; private boolean cleanupAfterInclude = true ; private MultipartResolver multipartResolver ; private LocaleResolver localeResolver ; private ThemeResolver themeResolver ; private List < HandlerMapping > handlerMappings ; private List < HandlerAdapter > handlerAdapters ; private List < HandlerExceptionResolver > handlerExceptionResolvers ; private RequestToViewNameTranslator viewNameTranslator ; private FlashMapManager flashMapManager ; private List < ViewResolver > viewResolvers ; public DispatcherServlet ( ) { } public DispatcherServlet ( WebApplicationContext webApplicationContext ) { } public void setDetectAllHandlerMappings ( boolean detectAllHandlerMappings ) { } public void setDetectAllHandlerAdapters ( boolean detectAllHandlerAdapters ) { } public void setDetectAllHandlerExceptionResolvers ( boolean detectAllHandlerExceptionResolvers ) { } public void setDetectAllViewResolvers ( boolean detectAllViewResolvers ) { } public void setThrowExceptionIfNoHandlerFound ( boolean throwExceptionIfNoHandlerFound ) { } public void setCleanupAfterInclude ( boolean cleanupAfterInclude ) { } @ Override protected void onRefresh ( ApplicationContext context ) { } protected void initStrategies ( ApplicationContext context ) { } private void initMultipartResolver ( ApplicationContext context ) { } private void initLocaleResolver ( ApplicationContext context ) { } private void initThemeResolver ( ApplicationContext context ) { } private void initHandlerMappings ( ApplicationContext context ) { } private void initHandlerAdapters ( ApplicationContext context ) { } private void initHandlerExceptionResolvers ( ApplicationContext context ) { } private void initRequestToViewNameTranslator ( ApplicationContext context ) { } private void initViewResolvers ( ApplicationContext context ) { } private void initFlashMapManager ( ApplicationContext context ) { } public final ThemeSource getThemeSource ( ) { } public final MultipartResolver getMultipartResolver ( ) { } protected < T > T getDefaultStrategy ( ApplicationContext context , Class < T > strategyInterface ) { } @ SuppressWarnings ( "unchecked" ) protected < T > List < T > getDefaultStrategies ( ApplicationContext context , Class < T > strategyInterface ) { } protected Object createDefaultStrategy ( ApplicationContext context , Class < ? > clazz ) { } @ Override protected void doService ( HttpServletRequest request , HttpServletResponse response ) throws Exception { } protected void doDispatch ( HttpServletRequest request , HttpServletResponse response ) throws Exception { HttpServletRequest processedRequest = request ; HandlerExecutionChain mappedHandler = null ; boolean multipartRequestParsed = false ; WebAsyncManager asyncManager = WebAsyncUtils . getAsyncManager ( request ) ; try { ModelAndView mv = null ; Exception dispatchException = null ; try { processedRequest = checkMultipart ( request ) ; multipartRequestParsed = processedRequest != request ; mappedHandler = getHandler ( processedRequest ) ; if ( ( mappedHandler == null ) || ( ( mappedHandler . getHandler ( ) ) == null ) ) { noHandlerFound ( processedRequest , response ) ; return ; } HandlerAdapter ha = getHandlerAdapter ( mappedHandler . getHandler ( ) ) ; String method = request . getMethod ( ) ; boolean isGet = "GET" . equals ( method ) ; if ( isGet || ( "HEAD" . equals ( method ) ) ) { long lastModified = ha . getLastModified ( request , mappedHandler . getHandler ( ) ) ; if ( logger . isDebugEnabled ( ) ) { logger . debug ( ( ( ( "Last-Modified<seq2seq4repair_space>value<seq2seq4repair_space>for<seq2seq4repair_space>[" + ( DispatcherServlet . getRequestUri ( request ) ) ) + "]<seq2seq4repair_space>is:<seq2seq4repair_space>" ) + lastModified ) ) ; } if ( ( new org . springframework . web . context . request . ServletWebRequest ( request , response ) . checkNotModified ( lastModified ) ) && isGet ) { return ; } } if ( ! ( mappedHandler . applyPreHandle ( processedRequest , response ) ) ) { return ; } mv = ha . handle ( processedRequest , response , mappedHandler . getHandler ( ) ) ; if ( asyncManager . isConcurrentHandlingStarted ( ) ) { return ; } <START_BUG> applyDefaultViewName ( request , mv ) ; <END_BUG> mappedHandler . applyPostHandle ( processedRequest , response , mv ) ; } catch ( Exception ex ) { dispatchException = ex ; } processDispatchResult ( processedRequest , response , mappedHandler , mv , dispatchException ) ; } catch ( Exception ex ) { triggerAfterCompletion ( processedRequest , response , mappedHandler , ex ) ; } catch ( Error err ) { triggerAfterCompletionWithError ( processedRequest , response , mappedHandler , err ) ; } finally { if ( asyncManager . isConcurrentHandlingStarted ( ) ) { if ( mappedHandler != null ) { mappedHandler . applyAfterConcurrentHandlingStarted ( processedRequest , response ) ; } } else { if ( multipartRequestParsed ) { cleanupMultipart ( processedRequest ) ; } } } } private void applyDefaultViewName ( HttpServletRequest request , ModelAndView mv ) throws Exception { } private void processDispatchResult ( HttpServletRequest request , HttpServletResponse response , HandlerExecutionChain mappedHandler , ModelAndView mv , Exception exception ) throws Exception { } @ Override protected LocaleContext buildLocaleContext ( final HttpServletRequest request ) { } protected HttpServletRequest checkMultipart ( HttpServletRequest request ) throws MultipartException { } protected void cleanupMultipart ( HttpServletRequest request ) { } protected HandlerExecutionChain getHandler ( HttpServletRequest request ) throws Exception { } protected void noHandlerFound ( HttpServletRequest request , HttpServletResponse response ) throws Exception { } protected HandlerAdapter getHandlerAdapter ( Object handler ) throws ServletException { } protected ModelAndView processHandlerException ( HttpServletRequest request , HttpServletResponse response , Object handler , Exception ex ) throws Exception { } protected void render ( ModelAndView mv , HttpServletRequest request , HttpServletResponse response ) throws Exception { } protected String getDefaultViewName ( HttpServletRequest request ) throws Exception { } protected View resolveViewName ( String viewName , Map < String , Object > model , Locale locale , HttpServletRequest request ) throws Exception { } private void triggerAfterCompletion ( HttpServletRequest request , HttpServletResponse response , HandlerExecutionChain mappedHandler , Exception ex ) throws Exception { } private void triggerAfterCompletionWithError ( HttpServletRequest request , HttpServletResponse response , HandlerExecutionChain mappedHandler , Error error ) throws Exception { } @ SuppressWarnings ( "unchecked" ) private void restoreAttributesAfterInclude ( HttpServletRequest request , Map < ? , ? > attributesSnapshot ) { }

Fix:
applyDefaultViewName ( processedRequest , mv ) ;